1. Aims The ECG complex Step by step interpretation Rhythm disturbances Axis QRS abnormalities Acute and chronic ischaemia Miscellaneous ECG abnormalities 1

2. The ECG Complex 2

3. (diagram of ECG complex) 3

4. Nomenclature P Wave QRS complex T wave U wave PR interval QT interval RR interval (ventricular) heart rate 4

5. Intra-cardiac electrical conduction (diagram of intra cardiac electrical conduction) 5

6. Standard 12 Lead ECG (Example of normal ECG) 6

7. Standard Times Interval (ms) PR 120 – 200 QTc (Corrected for heart rate) Men: 390-450 Women: 390-460 QRS <110 7

8. Step by step interpretation 8

9. Rate Rhythm Axis QRS complex ST segments 9

10. RATE 10

11. Rate Normal heart rate 60-100bpm Bradycardia < 60bpm Tachycardia > 100bpm Divide tachycardia into ‘broad’ and ‘narrow complex’ Broad = QRS > 110ms Narrow = QRS <110ms 11

12. Rhythm 12

13. Regular or irregular? Measure R-R interval between different complexes 13

14. Sinus rhythm Rhythm 14 (example showing sinus rhythm)

15. Where else may heart rhythm originate from? Atria –Atrial fibrillation –Atrial flutter –Atrial tachycardia In/around AV node – nodal ‘junctional’ rhythm –AVNRT/AVRT Ventricle –VT/VF * Will be demonstrated Rhythm 15

16. Atrial Fibrillation Erratic atrial depolarisation No discernible p waves Rate varies Irregular (example showing atrial fibrillation) Rhythm 16

17. Atrial Flutter Cyclical electrical activity around right atrium Atrial complexes occur at approx 300/min ‘Sawtooth’ appearance on ECG Almost always associated with degree of AV block (example showing atrial flutter) Rhythm 17

18. Junctional (Nodal) Rhythm Uncommon Rhythm arises from around AV node Narrow complex (example showing junctional rhythm) Rhythm 18

19. Accelerated ‘Idioventricular’ rhythm Unusual Heart rhythm controlled by ventricular focus Usually 60-120bpm (example showing idioventricular rhythm) Rhythm 19

20. Ventricular tachycardia Wide QRS Heart rate >120bpm Life-threatening (example of VT) Rhythm 20

21. Ventricular Fibrillation Rhythm 21 (example showing ventricular fibrillation)

22. Bradycardia Types –Sinus bradycardia (very rarely less than 40bpm) –Sick sinus syndrome –Slow AF/atrial flutter (usually drug related) –Atrioventricular (AV) block 22

23. Sinus Bradycardia (example showing sinus bradycardia) Rhythm 23

24. Sick Sinus Syndrome Sinus arrest (example of sinus arrest) Rhythm 24

25. AV block 1 st degree (prolonged PR interval) (example of 1 st degree AV block) Rhythm 25

26. 2 nd Degree AV block Mobitz type 1 (Wenckebach) (Example showing 2 nd degree mobitz type 1 block) Rhythm 26

27. 2 nd Degree AV block Mobitz type 2 (Example showing Mobitz type 2 2:1 AV block) Rhythm 27

28. AV Block 3 rd degree (complete heart block) (Example of complete heart block) Rhythm 28

29. Axis 29

30. Axis ‘Mean frontal plane axis’ Determined by vector of dominant (maximal QRS deflection) Normal:-30 to 90 degrees Left deviation-90 to -30 degrees Right deviation 90 to 180 degrees Axis 30

31. Axis 31 (diagram explaining axis alongside normal ECG)

32. Axis Check leads I and II If the complexes are both positive: normal If the complexes ‘Leave’ each other: Left If the complexes ’Reach’ each other: Right Axis 32

33. QRS abnormalities 33

34. QRS complexes Wide? (> 110ms) –Suggests either rhythm arising below AV node or –Conduction delay down bundle of his QRS abnormalities 34

35. Left bundle branch block QRS abnormalities 35 (diagrams of LBBB and diagram of leads V1 and V6)

36. Right bundle branch block QRS abnormalities 36 (diagrams of LBBB and diagram of leads V1 and V6)

37. Left/right bundle WiliaM MarroW QRS abnormalities 37 (diagrams of leads V1 and V6)

38. LVH/RVH LVH Criteria: –S wave in V1 + tallest R wave in V5 >35mm –Many other criteria –Caution when LBBB present RVH criteria: –Dominant R wave (>6mm) V1 –Deep S wave >10mm V5 or >3mm V6 38

39. Ischaemia 39

40. Ischaemic territories Ischaemia 40 (Illustrated example showing ischaemic territories)

41. Chronic ischaemia/ Q waves Normal in aVR/V1 > ½ small square wide and 1 small square tall (example of q wave) Ischaemia 41

42. Acute ischaemia T wave inversion (example of t wave inversion) Ischaemia 42

43. ST depression/elevation Describe how far J point is depressed/elevated from isoelectric line (diagram of j point) Ischaemia 43

44. Acute ischaemia ST depression (example of ST depression) Ischaemia 44

45. Acute ST elevation Ischaemia 45 (example of acute ST elevation)

46. Miscellaneous Abnormalities 46

47. Digoxin effect Miscellaneous abnormalities 47 (example of digoxin effect)

48. QT prolongation May be acquired or inherited (ECG of QT prolongation) Miscellaneous abnormalities 48

49. Hypokalaemia Miscellaneous abnormalities 49 (example of hypokalaemia)

50. Hyperkalaemia Miscellaneous abnormalities 50 (example of hyperkalaemia)

51. End of session 51